The use of sheet metal in the construction industry for roofing and/or siding material has long been known. One method of utilization comprises forming panel sections of a desired length and width from a roll of sheet metal in such a manner that a plurality of the panels may be interconnected to provide a substantially continuous roofing or siding surface.
Various types of sheet metal forming machines have been devised to address the needs of the construction industry by providing for the mass production of interconnectable sheet metal panels according to certain prescribed specifications. These machines typically have a frame structure which is sufficiently wide to allow various widths of sheet metal to be advanced therethrough. Positioned within this frame structure and attached thereto in a variety of manners are a plurality of laterally displaced roller assemblies. More particularly, a pair of substantially vertically aligned upper and lower rollers are successively positioned along two longitudinal and laterally displaced supports within the frame structure. The contours of these upper and lower rollers successively change such that the longitudinal edge portions of the sheet metal are gradually worked into the desired configuration.
A significant disadvantage associated with the known devices is that the rollers are used t onot only form the sheet metal, but are also connected to and rotated by an appropriate drive source to draw the sheet metal through the successive pairs of rollers. Since these rollers are typically metal so as to be able to adequately perform forming operations, the vertical spacing between each upper and lower roller must be sufficiently small in order for the rollers to sufficiently grip the sheet metal for advancement therethrough. More particularly, since there is metal-on-metal contact between the magnitude of frictional force required to advance the sheet metal, the vertically aligned rollers must be vertically separated less than the thickness of the sheet metal passing therethrough. Consequently, the sheet metal may, among other things, undergo an undesired deformation (i.e., a thinning of the sheet metal) in this region, subjecting the metal to increased stresses which could induce cracking and thereby affecting the panel's structural integrity and durability.
As can be appreciated, not every application will require panel sections of the same size (length and width). For instance, size requirements may vary from building to building. Moreover, panel size requirements within a single structure may in fact vary based upon the particular design being used (i.e., certain sections may need to be individually sized to accommodate for a given design). In order to address this need, existing sheet metal forming machines have also incorporated a width adjusting device for altering the width between the laterally displaced pairs of rollers. Additionally, such machines have also incorporated a cutting assembly to cut the panel sections into a desired length.
Existing width adjusting devices typically have one of the pairs of upper and lower rollers along the longitudinal supports remain laterally stationary. However, the oppositely-positioned succession of pairs of upper and lower rollers may be extended or retracted relative to the other pairs by an appropriate mechanism. As can be appreciated, if these laterally movable rollers are extended further away from their support it can become more difficult to generate the required frictional force to appropriately engage and move the sheet metal. Consequently, the sheet metal can advance at different rates through the succession of rollers on opposite edges producing an unsatisfactory end product (i.e., the sheet metal may become skewed relative to the rollers)
Thus, there is a need for a sheet metal forming device which reduces the amount of unwanted metal deformation and stresses within the sheet metal being formed. Moreover, there is a need for a sheet metal forming device which is adjustable to accommodate for the formation of various widths of sheet metal without adversely affecting forming operations.